Spark-ignited, fuel-injected internal combustion engines are often used in automotive vehicles. Fuel is injected into an intake system of such an engine by electric-operated fuel injectors of a fuel rail (sometimes referred to as a fuel manifold) assembled to the engine.
Targeted types of fuel injectors inject fuel into the vehicle engine in a direction, or directions, that are other than along the fuel injector axial centerline. A split stream fuel injector is an example of a targeted fuel injector. When a targeted fuel injector is used in an engine, the fuel injector has to have a particular angular or circumferential orientation about its centerline so that the direction(s) of fuel injection will be properly targeted. Improperly targeted fuel injectors may derogate engine performance and/or compliance with applicable vehicle emission requirements.
Proper targeting of a fuel injector typically requires a proper axial positioning of the fuel injector. This is typically achieved by positioning the fuel injector nozzle, which contains one or more metering orifices from which fuel is injected into an engine, in a fixed geometric relation to a socket receptacle of the engine intake system into which the nozzle is inserted in a sealed manner. When a fuel rail containing fuel injectors that have been properly circumferentially located in respective outlet cups of the fuel rail is assembled to an engine that has injector-receiving socket receptacles, the act of inserting the nozzles into properly sealed relationship with the socket receptacles can complete proper targeting of the fuel injectors. The achievement of the correct circumferential location of the fuel injector to the fuel rail outlet cup is referred to as “clocking” the fuel injector.
A fuel rail may comprise attachment features, apertured brackets for example, with which threaded fasteners are associated to fasten the fuel rail to an engine. Once the fuel injector nozzles have seated in properly targeted positions in the socket receptacles, a need for further tightening of such fasteners in order to secure the fuel rail on the engine may induce undesired stress, distortion and/or movement. For example, if fuel injector nozzles have been seated in properly targeted positions in respective socket receptacles in engine air intake manifold runners before the fuel rail attachment fasteners have been fully torqued, the fuel rail may distort in some way, and/or there may be some relative movement between some component parts, as the fasteners are finally tightened to full installation torque. With prevailing manufacturing methods and dimensional tolerances of manufactured parts, it seems that the possibility of such distortion, or movement of component parts, at time of fuel rail assembly to an engine, cannot be totally foreclosed in all circumstances.
It has been known to mechanically retain a fuel injector in a fuel rail outlet cup by a retention clip that constrains the two against any substantial movement, both circumferentially and axially. A fuel rail that incorporates such a capability may improve serviceability should it become necessary to remove the fuel rail from an engine and thereafter re-attach it.
Due to the enhanced stringency of vehicle emission requirements and the use of four-valve cylinder heads with two intake ports, it is now more important than ever to ensure that fuel injectors are properly clocked. Therefore the requirement that fuel injectors be properly clocked when inadvertently twisted during assembly or maintenance operations is greater than that previously required. Many prior fuel delivery system arrangements retain the fuel injector to the cup with a C-type clamp which when improperly torqued is subject to inadvertent opening.
It is desirable to provide a fuel delivery system arrangement for connecting the fuel injector between a fuel rail and air intake manifold of the vehicle engine wherein the clocking feature and the axial retention of the fuel injector to the fuel rail outlet cup can be separated.